1. Field of the Invention
The present invention relates to a grounding device for vehicles adapted to be suspended from the vehicle frame to make contact with the ground, thereby to electrically ground the vehicle frame.
More specifically, the invention is concerned with a grounding device for vehicles which has a conductive flexible strip suspended from a vehicle frame and contacting at its lower end with the ground to ground leaked electricity, static electricity, lightning and the like. The conductive flexible strip suspended from the vehicle frame is made of a conductive resilient strip material such as of conductive rubber, resin or the like. The conductive flexible strip is provided at its upper end with a fixture for attaching the strip to the vehicle frame, in such a manner as to permit elongation, shrinkage and movement of the strip. The conductive resilient strip is further provided with a reflector member having the dual functions of weighting the strip downwardly and of a reflector for warning a following vehicle. Also, a conductive metal wire is embedded in the conductive resilient strip to ensure the electric grounding.
2. Description of the Prior Art
Hitherto, safety grounding devices have been used for vehicles such as trucks carrying inflammable cargo such as gasoline. This type of safety grounding device has, as shown in FIG. 1 for example, a chain 3 suspended from the frame 2 of the automobile 1 for discharging the static electricity to the ground to prevent an electric charge from building up which could cause an accident.
This prior art safety grounding device making use of a chain can provide a good grounding of the vehicle frame, but the chain 3 is inevitably worn out rapidly or broken due to its bounding on the ground during running of the vehicle, often resulting in a grounding failure. Thus, in some cases, this type of safety grounding device cannot provide adequate grounding.
In addition, since the chain 3 is simply suspended from the frame 2 by virtue of its weight, the end of the chain 3 often bounces off the ground. Also, the chain can make only a point contact with the ground. For these reasons, the conventional chain type safety grounding device is often inadequate in grounding, its grounding effect resulting in an incomplete discharge of the electricity. Also, the electrostatic charge tends to build up until it finally results in an electrical discharge between the chain and the ground which produces noise in the vehicle radio.
In addition, conventional safety grounding devices employing a chain often suffer a grounding failure due to the deterioration of conductivity attributable to the accumulation of mud, dust, or the like on the links of the chain.
Further, the conventional prior art chain safety grounding device involves a danger of sparking between the chain and the ground during loading and unloading of gasoline at the gas station.
Also, vehicles are often equipped with various electrical instruments such as a starter motor, electronic fuel injection controller, running monitor, automatic door, microcomputer and so forth, all of which are grounded at their minus terminals. In consequence, the wiring of leads and circuits in the panel can impose a hazard of fire due to sparking, electric shock and the like if there is improper grounding. Also, with improper grounding, the vehicle frame can become electrically charged which can cause failure of the radio equipment.
Further, the conventional prior art safety grounding devices are not capable of completely obviating the danger of lightning.